The Interdisciplinary Research Methods Core (IRMC) will support the HIV Center's central research agenda, which focuses on understanding the interrelationship of gender, sexuality, and mental health in the context of HIV risk and on developing interventions designed to reduce the spread of HIV and improve long-term survival and quality of life of persons with HIV/AIDS. Over the past two decades, the IRMC and its precursor Cores have developed expertise in the conceptualization and assessment - qualitatively and quantitatively - of sexual risk behavior, gender scripts, and other aspects of sexuality; the investigation of psychological adaptation and of health behavior and attitudes; the formulation of risk-preventive interventions; and the application and adaptation of this expertise to cultures and countries beyond the US. The IRMC has three specific aims: (1) Project Consultation: To serve as the central advisory and oversight resource to HIV Center investigators on the characterization of study populations (especially determinants and contexts of people's sexual lives); conceptualization of explanatory models; development and implementation of interventions, on multiple levels where appropriate; and conceptualization and operationalization of outcomes, mediating factors, and intervention process factors; (2) Training and Education: To serve as a resource for Center-wide training in HIV-related sex research and prevention science including ethnographic/qualitative and quantitative approaches and instruments; and (3) Science Development: To serve as a venue for synthesizing emerging theoretical and methodological challenges in HIV-related sexual behavior and sexual-risk intervention science, with practical implications for public policy and for the planning of research. The IRMC centralizes the expertise of an interdisciplinary group of clinical and non-clinical specialists in diverse areas of HIV-related behavioral research and can, thereby, provide efficient consultations to investigators from project conception through the final phase of data interpretation and reporting. Investigators' utilization of the Core will alleviate major logistical and financial burdens of obtaining multi-disciplinary consultations during project development and implementation. In addition, Core members will participate in Center-wide training/education activities and in the dissemination of theoretical and methodological approaches beyond the HIV Center. The Core will also provide a forum for exchange among investigators from a variety of behavioral-science disciplines in the exploration of cutting-edge issues in HIV prevention science.